platform/chrome: wilco_ec: Fix keyboard backlight probing

The EC on the Wilco platform responds with 0xFF to commands related to
the keyboard backlight on the absence of a keyboard backlight module.
This change allows the EC driver to continue loading even if the
backlight module is not present.

Fixes: 119a3cb ("platform/chrome: wilco_ec: Add keyboard backlight LED support")
Signed-off-by: Daniel Campello <campello@chromium.org>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Signed-off-by: Benson Leung <bleung@chromium.org>

drivers/platform/chrome/wilco_ec/keyboard_leds.c

@@ -73,28 +73,33 @@ static int send_kbbl_msg(struct wilco_ec_device *ec,
 		return ret;
 	}
 
-	if (response->status) {
-		dev_err(ec->dev,
-			"EC reported failure sending keyboard LEDs command: %d",
-			response->status);
-		return -EIO;
-	}
-
 	return 0;
 }
 
 static int set_kbbl(struct wilco_ec_device *ec, enum led_brightness brightness)
 {
 	struct wilco_keyboard_leds_msg request;
 	struct wilco_keyboard_leds_msg response;
+	int ret;
 
 	memset(&request, 0, sizeof(request));
 	request.command = WILCO_EC_COMMAND_KBBL;
 	request.subcmd  = WILCO_KBBL_SUBCMD_SET_STATE;
 	request.mode    = WILCO_KBBL_MODE_FLAG_PWM;
 	request.percent = brightness;
 
-	return send_kbbl_msg(ec, &request, &response);
+	ret = send_kbbl_msg(ec, &request, &response);
+	if (ret < 0)
+		return ret;
+
+	if (response.status) {
+		dev_err(ec->dev,
+			"EC reported failure sending keyboard LEDs command: %d",
+			response.status);
+		return -EIO;
+	}
+
+	return 0;
 }
 
 static int kbbl_exist(struct wilco_ec_device *ec, bool *exists)
@@ -140,6 +145,13 @@ static int kbbl_init(struct wilco_ec_device *ec)
 	if (ret < 0)
 		return ret;
 
+	if (response.status) {
+		dev_err(ec->dev,
+			"EC reported failure sending keyboard LEDs command: %d",
+			response.status);
+		return -EIO;
+	}
+
 	if (response.mode & WILCO_KBBL_MODE_FLAG_PWM)
 		return response.percent;